The present invention relates generally to data transmission in mobile communication systems and, more specifically, to joint voice and data transmissions.
As used herein, the term “device” can refer to the terms “mobile station” (MS), “user agent” (UA), or “user equipment” (UE) which can include electronic devices such as fixed and mobile telephones, personal digital assistants (PDAs), handheld or laptop computers, smartphones, televisions and similar devices that have network communications capabilities. The terms may also refer to devices that have similar capabilities but that are not readily transportable, such as desktop computers, set-top boxes, IPTVs or network nodes. The term “MS” can also refer to any hardware or software component that can terminate a communication session that could include, but is not limited to, a Session Initiation Protocol (SIP) session. Also, the terms “mobile station”, “MS”, “user agent,” “UA,” “user equipment, “UE,” and “node” might be used synonymously herein. Those skilled in the art will appreciate that these terms can be used interchangeably.
An MS may operate in a wireless communication network that provides data and/or voice communications. For example, the MS may operate in accordance with one or more of an Enhanced Universal Terrestrial Radio Access Network (E-UTRAN), Universal Terrestrial Radio Access Network (UTRAN), Global System for Mobile Communications (GSM) network, Evolution-Data Optimized (EV-DO), 3GSM, Enhanced Data rates for GSM Evolution (EDGE), GPRS/EDGE Radio Access Network (GERAN) and General Packet Radio Service (GPRS) technology. Some MSs may be capable of multimode operation where they can operate on more than one access network technology either on a single access network at a time or in some devices using multiple access technologies simultaneously.
In wireless telecommunications systems, transmission equipment in a base station transmits signals throughout a geographical region known as a cell. The base station comprises a scheduler for dynamically scheduling downlink traffic transmissions and allocating uplink traffic transmission resources among all MSs communicating with the base station on a number of timeslots. The functions of the scheduler include, among others, dividing the available air interface capacity between MSs, deciding the transport channel for each MS's transmissions, and monitoring allocation and system load.
Communication networks may implement circuit-switched (CS) and/or packet-switched (PS) communication protocols to provide various services. The different networks described above, for example, may be configured to provide various services to connected MSs. Some networks, for example, provide only PS services and cannot provide CS voice or other CS domain services. As such, an MS may be configured to connect to multiple network-types to access both PS and CS domain services.
In some cases, networks (e.g., GERAN) and connected MSs are configured to allow for the simultaneous communication of CS and PS-based communications. For example, dual-transfer mode (DTM) may be provided by GERANs to allow for CS voice and PS data transfers between, for example, a MS and a base station. Generally, there are two classes of DTM. The first DTM class includes multi-slot DTM. In multi-slot DTM voice (e.g., CS voice) and data (e.g., PS data) traffic are transmitted using separate timeslots of a TDMA frame. Accordingly, the voice and data communications are not transmitted simultaneously (or within the same timeslot). Instead, the voice and data traffic may be transmitted using timeslots of a TDMA frame. A second DTM class includes single-slot DTM. In single-slot DTM a combination of half-rate speech traffic channel and half-rate packet data are communicated via the network (see, for example, 3GPP TS 45.002). In that case, even though the voice and data traffic may be transmitted within the same timeslot, each type of data is treated separately and transmitted within the same time slot in alternating TDMA frames, as an example.
FIG. 1 is a block diagram illustrating the operation of existing DTM schemes. As shown in FIG. 1, the system includes two separate information paths. The first path is configured to process voice bits 50, while the second path is configured to process data bits 52. The voice bits may be generated by, for example, a speech encoder contained with an MS or other network communications equipment. In the voice path, voice bits 50 are processed by processing block 54. After processing, the processed voice bits are allocated to resource 56 for transmission. Similarly, in the data path, data bits 52 are processed by processing block 58. The data bits may be generated, for example, by a processor in the MS or other network communications equipment. After processing, the processed data bits are allocated to resource 60 for transmission. In existing systems, resources 56 and 60 are separate. The resources may be different bursts within the same timeslot, or may, in fact, be located in different timeslots or on different frequencies. Accordingly, in some network implementations, both the voice and data bits are processed separately, encoded separately, and transmitted using separate resources.
As such, existing DTM schemes multiplex data on separate resources: either on separate time slots (in the multi-slot DTM schemes), or in one time slot but in alternating TDMA frames (in the single-slot DTM case). Accordingly, in existing DTM implementations, voice and data traffic are treated separately and transmitted using separate resources. This behavior results in inefficient utilization of available network resources.